The invention relates to a method for accelerating air- or gas-exchange, and reducing operating energy during filling and/or discharge of pressure chamber.
In a method of the aforedescribed type there arise, on one hand, uneconomic energy costs in an initial phase of the filling of the pressure chamber, until a pressure slightly above atmospheric pressure has been reached, as air or gas compressed in a compressor to a higher pressure than atmospheric pressure expands again during passage into the empty pressure chamber through a conduit. On the other hand, the use of a blower for the same purpose, although requiring less energy, requires additional time in order to reach a minimal filling degree at a considerably lower filling capability, which, in turn, has a disadvantageous effect on the efficiency of filling the pressure chamber.
Similar circumstances prevail during discharge of a pressure chamber with a subsequent build-up of a vacuum. Here during opening of a valve a falling-off of the pressure peak is obtained relatively quickly, while falling-off of the pressure beyond that of the atmosphere, and a subsequent build-up of a vacuum can only be accomplished at a relatively high expenditure of energy, or, in the event a blower is used, by the process time being considerably extended.
A pressure chamber of this type can serve both for the storage of compressed air and compressed gases, as well as for the separation of liquid materials from solid materials.
Thus there are known, for example, devices for separating solid materials from liquid materials, which include a rotatably supported press container, which is partitioned by a flexible membrane into a pressure chamber and a pressing space, and wherein an inlet is associated with the pressure chamber for passing a pressure medium thereinto, and an outlet is associated with the pressing space for a liquid to be squeezed out therefrom, and wherein the pressure chamber is filled with compressed air obtained from a compressor until attainment of the compression pressure.
Experience has shown that in an arrangement of this type a third of the air volume to be introduced into the pressure chamber for the purpose of squeezing out a compressible agricultural product such as a mash is required just to shift the membrane normally abutting the container wall under vacuum from that wall to the mash, so that the membrane makes contact with the mash.
Compression of air by means of a compressor, for the purpose of causing the membrane to abut an agricultural product such as a mash, is not sufficiently efficient, and it is equally unsatisfactory to draw or suck off any remaining air from the pressure chamber by means of a blower following normal discharge of air therefrom.
This also applies for filling or discharge of a pressure chamber for storage therein of gases or of air.
If desired, such devices can be provided with an additional blower, which takes over the task of causing the membrane to abut the mash; devices using such features are known in practice. Hence it is possible to obtain an inlet pressure, and suctioning off of the air from the pressure chamber, while expending less energy than hitherto. A disadvantage here, however, is the longer operating time, which is increased based on several operating cycles.